1. Field of the Invention
This invention relates generally to a gas lighter having a main body portion that forms a closed compartment for containment of a combustible fluid under pressure, an upper end portion on which is mounted a normally closed valve means communicating with said compartment for release of said fluid in a gaseous state, and a pushbutton that is engaged with the valve means and is depressible for operation of the valve means to an open condition that releases said fluid in said gaseous state; more particularly, to such a lighter wherein the pushbutton is normally blocked against depression by means of a stop member that is slidably mounted on the lighter's upper end portion under the pushbutton so as to normally block depression of the pushbutton but which stop member can be moved to an unblocking position by thumb pressure applied to an actuator portion of such stop member that projects from a rearward end of the lighter's upper end portion; and specifically, to such an arrangement wherein a lower surface of the pushbutton normally stands upon a portion of the stop member that defines a blocking member, wherein the actuator is pushed first inwardly in order to slide a top surface of the blocking member to a position longitudinally removed from the pushbutton's lower surface, and then pushed upwardly in order to bring an outer side of such blocking member into a resiliently maintained frictional contact with an inner side of the pushbutton whereby the pushbutton is placed in an unlocked condition and the actuator can then be released and the thumb applied to the pushbutton for depression of it, and wherein, upon depression and release of the pushbutton the blocking member's top surface is returned to its initial position under the pushbutton's lower surface by the return bias of resilient arm members which form part of the actuator and which flex against outboard surfaces of the lighter's upper end portion in order to produce the return bias that is effective upon the blocking member.
For present purposes such a lighter shall be understood to have a longitudinal axis that extends across forward and rearward portions of the lighter's upper end portion, "so as to include and intersect said forward and rearward portions". The term "longitudinally" as used herein means in a direction parallel to said longitudinal axis, and the term "laterally" as used herein means cross-wise to such longitudinal axis.
A disposable lighter conventionally includes a main body portion defining a closed compartment that contains or is fillable with a combustible fluid under pressure, an upper end portion on which is mounted a normally closed valve means communicating with the fuel compartment for release of the fuel in a gaseous state, means defining a pushbutton that is connected with the valve means for operation of the valve means to an open condition the releases the combustible gas in response to depression of the pushbutton, and, means operable substantially simultaneously with depression of the pushbutton, producing a spark or sparks for ignition of the released gas to produce a flame.
The term "pushbutton" as used herein means that element which is pressed by thumb to operate the valve means to its gas-releasing open condition, and for present purposes it does not matter whether such pushbutton is formed by one end of a pivotally mounted lever or is a true pushbutton as in a piezo-electric lighter.
In all such lighters the pushbutton has a given normal elevation on the lighter's upper end portion and is depressible against the resistance of means biasing the pushbutton to return to its normal elevation. Conventionally, if the pushbutton is defined by the rearward end of a pivotally mounted lever the pushbutton-biasing means may be a spring that is incorporated in the valve means in order to bias the valve means normally closed but simultaneously also biasing the pushbutton by virtue of the engagement of a forward end of such lever with the valve means for operation of the valve means to its open condition by depression of the pushbutton. The prior art also provides such a pivotally mounted lever having a helical compression spring mounted directly under the pushbutton; i.e., between the pushbutton and the lighter's upper end portion. Recent prior art also provides a lighter having a pivotally mounted lever that has resilient legs formed integrally with an underside portion of the lever in an arrangement functioning as the pushbutton-biasing means. In the case of a piezo-electric lighter a spring incorporated in a compressible spark-generating device biases a pushbutton that is mounted at the upper end of such device.
The accompanying drawings illustrate a lighter wherein a lever extends longitudinally of the lighter's upper end portion and is pivotally mounted thereon between a pair of tab members which form part of the lighter's upper end portion. A rearward end of the lever defines a pushbutton and a forward end of the lever is engaged with a valve means that incorporates a spring that, as described above, biases the valve means normally closed, but there is also provided a helical compression spring mounted between the pushbutton and the lighter's upper end portion in order to directly bias the pushbutton to return to its normal elevation after depression and release.
Lighters in which a lever defines the pushbutton typically utilize an ignition means comprising a flintwheel that is rotatably mounted between the tab members overlying the lever, the flintwheel being rolled substantially simultaneously with depression of the pushbutton and abrading an underlying flint that generates sparks that ignite the released gas. The flint and an underlying flint-biasing spring that urges the flint into contact with an abrasive periphery of the flintwheel are mounted in and are supported by a flint-support column that rises from the lighter's upper end portion between the tab members, with an upper end of such column passing through a central opening in the lever in order to permit the flint to access the flintwheel. The said central opening in the lever defines what are herein termed "beam member portions" of the lever, reference being made to those portions of the lever intermediate its length which extend longitudinally of the lighter's upper end portion and are mounted between opposite sides of said flint-support column and the adjacent inboard sides of said tab members, the beam member portions conventionally being provided with lateral projections which are received in openings provided in the tab members whereby the lever is pivotally secured to the tab members for limited movement about a pivot axis. Conventionally, these beam member portions of the lever are mounted at an elevation on the tab members and as a result of such elevated mounting a free or open space conventionally exists between these beam member portions and the lighter's upper end portion on each side of the flint-support column. The present improvement preferably utilizes these spaces to receive the terminal ends of a pair of leg members which form the forward end of the stop member that makes the invention lighter child-resistant.
U.S. Pat. No. 5,242,297 referenced at the outset hereof under Related Application Data and not considered prior art, discloses a lighter wherein the pushbutton is normally blocked against depression by means of a stop member that is slidable longitudinally upon the lighter's upper end portion under a lower surface of the pushbutton, wherein the stop member includes an actuator portion thereof that projects from the rearward end of said upper end portion and is pushed first upwardly in order to unlock the actuator, and then pushed inwardly in order to move a blocking member of the stop member to a position longitudinally removed from a normal blocking position under said lower surface whereby a clearance adjacent the blocking member permits depression of the pushbutton, and wherein a forward end of the stop member remote from the actuator includes a pair of resilient arm members in the form of a U-shaped loop that is mounted within a recess provided in said upper end portion, the U-shaped loop being so arranged that the actuator is pushed inwardly against the resistance of said resilient arm members which then impart a longitudinally-directed return bias to the actuator and to the blocking member whereby the pushbutton is automatically returned to its normally locked condition. This arrangement has been found to be limited because of the inboard location of the resilient arm members which return bias the actuator and the blocking member. Where the stop member is a plastic molding in which the resilient arm member have thick cross-sections for ruggedness and as a result are relatively bulky, such inboard location of the resilient arm members reduces the space available for movement of the blocking member from its normal blocking position to its unblocking position under the pushbutton's lower surface. It is desired to provide an arrangement wherein the actuator must be pushed inwardly a substantial distance in order to move the blocking member from its blocking to its unblocking position, so that such operation of the actuator must be done deliberately and a child is not likely to do it by accident.
Major producers currently market child-resistant lighters having a rearwardly-located actuator that must be pushed first inwardly and then upwardly in order to unlock the pushbutton and so consumers have become conditioned to accept and have found convenient such mode of operation of the safety feature. Accordingly, it is desired to provide a child-resistant lighter having a similar first inward and then upward mode of operation of the actuator, but in combination with the child-resistancy enhancing advantage of requiring a substantial inward movement of the actuator in order to effect a corresponding substantial longitudinal movement of the blocking member from its pushbutton blocking to its pushbutton unblocking position. The present improvement attains this additional safety feature by forming the resilient arm members as part of the actuator itself so that the resilient arm members are mounted externally of the lighter body and as a result there is a sufficient free space inboard of the lighter body for the blocking member to be moved longitudinally the desired substantial distance in response to a corresponding substantial inward movement of the actuator.
The prior arrangement was further limited in that because the U-shaped resilient arm members are formed dependent from the blocking member portion of the stop member (for mounting in the recess), the stop member has a complex shape requiring a complex mold design. It is desired to provide an arrangement attaining the features described above by means of a stop member that is in the form of a substantially flat one-piece plastic member having a thick cross-section and the simplest possible shape so that such stop member is easy to mold using a die of least costly design, that is easy for a machine to handle and install in the lighter, and which, due to the ruggedness flowing from such proportions and shape will be absolutely reliable in operation and will not be dependent for such reliability upon maintenance of close manufacturing tolerances.
The present improvement provides an arrangement wherein the lighter's upper end portion is provided with a pair of wall members that define a single narrow slot at the rearward end of the lighter. An inboard portion of the stop member is mounted between laterally spaced apart inboard surfaces of such wall members. A neck portion of the stop member extends through and projects rearwardly of the slot and defines an actuator that includes a pair of resilient arm members which are spaced apart from but have free ends which are slidably engaged with outboard surfaces of the wall members, such that, when the actuator is pushed inwardly toward the slot (guided by said neck portion sliding within the slot), the free ends of the resilient arm members are forced to flex so as to impart a longitudinally-directed return bias to the actuator and thereby to the stop member as a whole. A lower surface of the pushbutton normally stands upon the top surface of a blocking member portion of the stop member whereby the pushbutton is normally blocked against depression. When the actuator is pushed inwardly, the blocking member is moved to a position longitudinally removed from the said pushbutton lower surface and a clearance is thereby produced adjacent to such blocking member that permits depression of the pushbutton for operation of the valve means to its gas-releasing open condition. However, the blocking member must be held in such longitudinally moved position. By pushing the actuator upwardly-while still holding it pushed inwardly--an outer side of the blocking member is lifted to a position longitudinally opposed to and in frictional contact with an inner side of the pushbutton. The actuator can then be released because the said frictional contact will hold the blocking member in its inwardly and upwardly moved position. The pushbutton is thereby caused to remain in an unlocked and depressible condition, the pushbutton being then depressible because the clearance mentioned above will then be under the blocking member portion of the stop member. Depression of the pushbutton pushes the blocking member back down to its normal elevation, and when the pushbutton is released, the return bias of the resilient arm members pulls the blocking member back under the pushbutton's lower surface whereby the pushbutton is automatically returned to its normally locked condition.
2. Description of Prior Art
Morris, Sr., U.S. Pat. No. 4,832,596 discloses a child-resistant lighter wherein a stop member is biased by spring means mounted externally of the lighter body, but having an actuator that is mounted at the forward end of the lighter body and has to be pulled inwardly with one's index finger, against the resistance of a coil spring or rubber pad that is mounted between the actuator and the forward end of lighter body, in order to hold the stop member in an unblocking position out from under the pushbutton while as the same time using one's thumb to depress the pushbutton. This arrangement is severely limited because of the forward location of the actuator which requires and awkward performance of two manipulations which are extremely difficult to do simultaneously.
Iwahori, U.S. Pat. No. 5,205,729 discloses a child-resistant lighter having wall members defining a single slot at the rearward end of the lighter's upper end portion and a stop member that includes a neck portion that is restricted to sliding longitudinally in the slot and defines the actuator portion of the stop member, but having a pair of resilient arm members mounted inboard of the wall members, and the pushbutton being unlocked merely by pushing the actuator inwardly toward the slot, a blocking member of the stop member being held at its inwardly moved unblocking position by means of an "action member" which is an integral part of the lighter's upper end portion and defines a resiliently depressible hook that functions to hook the stop member so as to hold it at its inwardly moved position until the pushbutton is depressed whereby the action member is pushed downwardly out of engagement with the stop member. Among other limitations, including unnecessary complexity, Iwahori's arrangement provides the minimum level of child-resistancy because the pushbutton is unlocked by pushing the actuator in only one direction; no other movement of it is required.
The present arrangement provides a higher level of child-resistancy because the actuator has to be pushed in two distinctly different directions and has the further advantage that, because the present actuator's return biasing means is located externally of the lighter body, the inboard portion of the stop member is free to be utilized as a means of positively stabilizing movement of the actuator; specifically, by defining a pair of rigid straight leg members which are spaced apart parallel to each other so that they can slide longitudinally under the beam member portions of the lighter's pushbutton-defining lever whereby longitudinal movement of the actuator is stabilized, with terminal ends of the leg members preferably being confined such that they define a secured fulcrum for the actuator that causes the actuator to pivot when pushed upwardly by thumb pressure and when pushed downwardly by depression of the pushbutton, this secured pivoting action of the actuator positively stabilizing such up and down movement of the actuator.
The present arrangement provides optimum child-resistancy by necessarily requiring the actuator to be moved in two distinctly different directions, and this added safety factor is attained by structure so arranged that one cannot unlock the pushbutton merely by pushing the actuator with a greater force in one direction or the other, or by applying such force on a vector that pushes the actuator in both directions at once. Accordingly, the possibility that an experimenting child will place the pushbutton in an unlocked condition is held to a reasonably attainable minimum.
The present arrangement provides optimum left-handed and right-handed user convenience by providing the actuator located at the rearward end of the lighter body, the actuator being pushed first inwardly a substantial distance in order to unblock the pushbutton, and then upwardly, in order to hold the pushbutton in its unblocked condition. The user is provided with a sure grip and comfortable feel for pushing the actuator upwardly by virtue of the actuator extending laterally across the rearward end of the lighter body and having slim proportions and an arcuate shape substantially conforming to the typical curvature of the lighter body whereby the actuator is comfortably received by one's thumb.
Kenjiro, et al., U.S. Pat. No. 5,240,408 (hereinafter abbreviated to "'408") provides an actuator having such desirable shape but in an arrangement having a significant functional limitation, identified below, which the present arrangement avoids.
In '408 a pair of wall members rise from the rearward portion of the lighter's upper end portion, as in the present improvement, but instead of a single narrow slot being defined by these wall members at the rearward end of the lighter's upper end portion (as in the present arrangement)in '408 the wall members are provided with a pair of slits which between them define a "resilient leaf" that has a lower end contiguous with the lighter's upper end portion and has an upper end that is curved inwardly toward the lighter's pushbutton. The inwardly curved upper end of the resilient leaf is normally received in a "recess" formed in the underside of the pushbutton, whereby the pushbutton is normally blocked against depression. Accordingly, '408 does not utilize a distinct stop member that is slidable longitudinally on its upper end portion.
In order to unlock the pushbutton so that it can be depressed, the upper end of the resilient leaf must be caused to move outwardly away from the pushbutton so as to be removed from the recess and thereby provide a clearance for depression of the pushbutton. This is accomplished by means of a "lock lever" that is mounted on and is slidable up and down upon the resilient leaf. The lock lever is normally positioned at the lower end of the resilient leaf. When the lock lever is pushed to the upper end of the resilient leaf, it does not follow the inward curvature of the resilient leaf but instead travels a straight path defined by edges of the wall members which edges stand adjacent to the resilient leaf, and as a result, the lock lever forces the upper end of the resilient leaf to flex outwardly away from the pushbutton and out of engagement with the recess. This arrangement is inherently incapable of providing the substantial inward movement of the actuator that is provided by the present improvement. The limited inward movability of the actuator of '408 adversely impacts the level of child-resistancy that is provided. It has been found by examination of marketed specimens of such lighter that the pushbutton can be unlocked and caused to remain in its unlocked condition merely by pushing the actuator in only a single direction, upwardly, with greater force, or, by pushing the actuator on a vector that causes the actuator to move both inwardly and upwardly simultaneously. The following discusses the cause of this limitation.
The lock lever of '408 comprises a basically rectangular annular member that forms a closed loop encircling the resilient leaf; such that, the longer sides of the rectangle are positioned one inboard and one outboard of the resilient leaf. The longer side of the rectangle that is positioned outboard of the resilient leaf defines an actuator portion of the lock lever. This actuator portion extends laterally across and slightly beyond adjacent sides of the resilient leaf and it has the above preferred laterally slim arcuate shape substantially corresponding to the curvature of the lighter body. The shorter sides of the rectangle are normally parallel to each other, extend through the slits, and, of course, join the inboard side of the lock lever with the outboard or actuator side of the lock lever.
Extremities of the actuator define "deformable legs" which hook onto and ride upon the above mentioned wall member edges which stand adjacent to the resilient leaf. The function of the "deformable legs" of '408 is demonstrable by cutting them off the lock lever and observing what function is lost. In the absence of the deformable legs the lock lever of '408 hangs loosely upon the resilient leaf and looses its ability to force the upper end of the resilient leaf out of engagement with the recess. The pushbutton remains permanently locked and there is no way to unlock it. Accordingly, the function of the deformable legs is to provide the lock lever with leverage, which the deformable legs obtain against the wall member edges which stand adjacent to the resilient leaf. The deformable legs ride upon these edges when the lock lever is pushed upwardly and thereby guide the lock lever as well as provide leverage for it to push the resilient leaf out of the recess. The deformable legs are so termed because a sufficient inwardly-directed thumb pressure applied to the actuator will force an outward deformation of the deformable legs by means of which "engaging elements" which are provided on the inboard portion of the lock lever and are normally engaged with the resilient leaf so as to normally prevent upward movement of the lock lever are caused to become disengaged from the resilient leaf so that the lock lever can then be pushed upwardly. But since longitudinal movement by deformation is inherently slight (as opposed to significant longitudinal movement enabled by resilient arm members), the engaging elements do not reliably serve their intended purpose and it is frequently possible to push the actuator directly upwardly without having to first push it inwardly, the upward push alone forcing the engaging elements out of their normal engagement with the resilient leaf.
In '408 the actuator is in the form of a cross-bar that has its opposite ends fixed to and supported by the spaced apart pair of members (the shorter sides of the rectangle) that project through the slits. Accordingly, Inwardly-directed thumb pressure applied to the actuator forces inward deformation of only that central portion of the actuator that extends between the said pair of members that extend through the slits, such inward pressure simultaneously forcing outward flexure of the deformable legs whereby the inward movement of the actuator is enabled, the deformable legs remaining longitudinally stationary upon the supporting edges of the wall members in order to provide leverage for compression of such central portion of the actuator. This arrangement produces only a slight longitudinal movement of the engaging elements for effecting their disengagement from the resilient leaf. Since the engaging elements must be releasable from the resilient leaf by such a slight longitudinal movement of them, the intended safety feature is not fail-safe but is subject to defeat by flexure of the engaging elements out of the recesses which are provided in the resilient leaf in which recesses the engaging elements are normally received, a certain amount of flexure of the engaging elements being unavoidable because the material from which the lock lever is made must be resilient in order for the central portion of the actuator to be compressible and the deformable legs to be deformable.
In the present arrangement the central portion of the actuator is not flexible (as in '408) but is instead fixed to and rigidly supported by the neck portion of the stop member, the ends of the actuator being free and resiliently flexible. This arrangement permits substantial longitudinal movement of the blocking member whereby it can be provided with a relatively broad top surface, and as a result, only a substantial longitudinal movement of the blocking member will remove it from its normal blocking position under the pushbutton's lower surface, and any flexibility inherent in the material from which the blocking member is made cannot adversely affect child-resistancy. No matter how hard one pushes the actuator upwardly the pushbutton will remain locked until the user first pushes the actuator inwardly far enough and then pushes it upwardly.
The accompanying drawings illustrate a preferred embodiment wherein the stop member is a substantially planar one-piece member having (a) an inboard portion mounted between wall members which are formed on and define a slot at the rearward end of the lighter's upper end portion, (b) a neck portion that extends through and projects rearwardly of said slot, (c) an actuator portion that is formed like a cross-bar that has its midpoint fixed to the projecting end of said neck portion and has an arcuate shape defining a pair of resilient arm members which originate from the neck portion of the stop member and have free ends slidably engaged with outboard surfaces of said wall members, (d) a pair of rigid leg members which are spaced apart parallel to each other and extend from the inboard portion of the stop member in a direction opposite from where the actuator is located, and (e) a blocking member formed near the neck portion having a top surface that normally underlies a cooperating lower surface of the pushbutton so as to normally block its depression.
FIGS. 4 and 5 of McDonough et al., U.S. Pat. No. 5,125,829 (hereinafter referred to as "'829") show a stop member at first glance resembling that described above but in fact differing significantly both structurally and functionally as follows. To facilitate comparison, terms which are employed herein to describe aspects of the invention stop member are applied to the corresponding structure of '829 unless otherwise indicated by placement within quotation marks.
First, and most significantly because the shape and function of all portions of the stop member of '829 are determined by this essential underlying difference, the stop member of '829, indicated generally in the drawings thereof as (16), is not slidable longitudinally upon the lighter's upper end portion. It has an actuator portion (54) that is structured for movement first "in a lateral direction" and then upwardly in order to position a neck portion (44) in frictional contact with either one of two laterally opposite sides (40) or (42) of a dependent portion of the lighter's pushbutton. This lateral movability of the actuator (54)is shown in FIGS. 9-12 of '829, wherein the numeral (16)indicates the stop member generally and the specification thereof identifies same as "safety latch 16".
In order to permit the lateral movability depicted in FIGS. 9-12 of '829, the lighter body has to define a slot (25), FIGS. 1 and 2, that permits lateral movability of the actuator (54) alternately in opposite directions relative to a normally centered position of the actuator (54)in the slot (25). This contrasts with the present arrangement wherein the lighter body has a slot that prevents lateral movability of the actuator.
In '829 the actuator (54) has a laterally-directed return bias that returns the actuator (54) to its normally centered position in slot (25). This contrasts with the present arrangement wherein the actuator has a longitudinally-directed return bias.
In '829 the laterally-directed actuator-biasing means is mounted inboard of the lighter body. This contrasts with the present arrangement wherein the actuator-biasing means is mounted outboard of the lighter body.
In '829 the laterally-directed actuator-biasing means comprises a C-shaped open loop that is contiguous at a midpoint thereof with the neck portion (44) and has diverging extensions of such loop defining a pair of resiliently flexible leg members (50, 52). This contrasts with the present arrangement which has a pair of rigid leg members which are wholly straight and spaced apart parallel to each other in order to be slidable longitudinally between the flint-support column and the tab members which support a pivotally mounted lever that defines the lighter's pushbutton.
In '829 the actuator (54)is wholly rigid, has no portion that is flexible, has its free ends always spaced apart from the lighter body, and functions solely as a gripping means for actuation and not as a return-biasing means. This contrasts with the present arrangement wherein the actuator defines a pair of resilient arm members which have free ends that are always engaged with and are resiliently flexible against outboard surfaces of the lighter body in order to function as a return-biasing means.
In '829 the neck portion (44) simultaneously defines a blocking member (44) of the stop member. A pushbutton lower surface (48) normally stands upon a top surface (46) of the neck or blocking member (44) whereby the pushbutton (34) is normally blocked against depression. In order to unlock the pushbutton (34), the actuator (54) is pushed first laterally one way or the other relative to the pushbutton's lower surface (48), and then upwardly. This contrasts with the present arrangement wherein the actuator is first pushed inwardly; i.e., longitudinally, before being pushed upwardly. In '829 the initial lateral movement brings the blocking member's top surface (46)into a position laterally removed from the pushbutton's lower surface (48). This contrasts with the present arrangement wherein the blocking member is moved into a position longitudinally removed from the pushbutton's lower surface. In '829, while holding the blocking member's top surface (46)in its laterally removed position from the pushbutton's lower surface (48), the actuator (54)is then pushed upwardly in order to bring one of two laterally opposite sides of the blocking member (44)into a laterally opposed frictional contact with a cooperating lateral side (40) or (42) of the pushbutton (34). This contrasts with the present arrangement wherein longitudinally opposed sides of the blocking member and pushbutton are brought into a longitudinally opposed frictional contact.
In '829, the laterally opposed frictional contact is resiliently maintained by flexure of the internally located resilient leg members (50, 52) which define a forward end of the stop member and function to impart a laterally-directed return bias to the blocking member (44). This contrasts with the present arrangement wherein the longitudinally opposed frictional contact is resiliently maintained by flexure of externally located resilient arm members which impart a longitudinally-directed return bias to the blocking member, and wherein the forward end of the stop member defines a pair of rigid leg members which function solely to stabilize movement of the actuator.
Finally, a child-resistant lighter currently marketed by a major producer has a pivotally mounted lever mounted on an upper end portion of the lighter body. A rearward end of such lever defines a pushbutton. The pushbutton is depressible against the resistance of a helical compression spring that is mounted directly under the pushbutton and biases the pushbutton to return to a given normal elevation on the lighter's upper end portion. A combination pushbutton blocking member and actuator has the actuator portion thereof projecting rearwardly of the lighter's upper end portion through a single slot that is provided in the rearward end of the lighter's upper end portion. A distinct element comprising a metal leaf spring is mounted inboard of the lighter's upper end portion. The leaf spring comprises a single arm that is positioned vertically, has its lower end fixed to the lighter body and has its upper end resiliently flexible in only a single direction, said direction being longitudinally of the lighter's upper end portion as the term "longitudinally" has been defined herein. The actuator/blocking member is mounted on the upper end portion of said leaf spring so as to be slidable up and down upon same. An upper end of the actuator/blocking member normally underlies and blocks depression of a lower surface of the pushbutton. The normally locked pushbutton is unlocked by pushing the actuator/blocking member first inwardly toward the slot, and then upwardly toward the pushbutton. The inward movement is enabled by flexure of the leaf spring, the resistance of which imparts a longitudinally-directed return bias to the actuator/blocking member. The upward movement is enabled by the vertical slidability of the actuator/blocking member upon the leaf spring. Said upward movement brings an outer side of the actuator/blocking member into a position longitudinally opposed to and in frictional engagement with an inner side of the pushbutton whereby a clearance is produced under the pushbutton's lower surface that renders the pushbutton depressible, the said frictional engagement being resiliently maintained by the return bias of the leaf spring acting upon the actuator/blocking member. Depression of the pushbutton pushes the actuator/blocking member back down to its initial elevation on the leaf spring, and when the pushbutton is released and returns to its normal elevation, the actuator/blocking member is returned to its initial position under the said lower surface of the pushbutton by the return bias of the leaf spring, whereby the pushbutton is automatically returned to its normally locked condition. That portion of the leaf spring upon which the actuator/blocking member is mounted is bent to define bumps that function to impede up and down slidability of the actuator/blocking member upon the leaf spring, such impedance being slight and not noticeable to the user of the lighter but being sufficient to ensure that the actuator/blocking member remains in its depressed position and does not follow the pushbutton when the pushbutton is depressed and then released.
The above described arrangement of the safety feature is limited by unnecessary complexity--it necessarily has to comprise two parts so that one part can be movable relative to the other. A further limitation is that the portion of the actuator/blocking member that defines the actuator per se is in the shape of a rectangular button that is positioned vertically and such shape is not easy for the user's thumb to obtain a grip on for pushing upwardly. A further limitation is that the leaf spring comprises a strip of metal having a loop formed at it lower end which must be forcibly pressed into a recess provided in the upper end portion of the lighter, a mode of installation which requires precision handling by machine and, due to the narrow width and thinness of such strip of metal, the possibility of its bending when being pressed into the recess. And finally, because it is necessary to provide a recess for holding the lower end of the spring, structure must be added to the main body portion of the lighter for defining said recess, and said added structure necessitates a slight reduction of the volume of the fuel compartment.
These limitations contrast with the present arrangement wherein the stop member comprises a single element, the actuator portion of such stop member extends laterally across the rearward end of the lighter and therefore inherently has a shape that is easy to push upwardly by thumb, the stop member is a relatively large element so that it is easy to handle by machine and is rugged because of its "chunky" design whereby it is not likely to break or deform, it does not require a high degree of precision in handling for installation, and since it is mounted wholly upon the upper end portion of the lighter body it has no effect upon the capacity of the fuel compartment.
The above has discussed all that prior art which is believed to most closely approach the present improvement and no more pertinent prior art is presently known.